A microorganism of the genus Corynebacterium, particularly Corynebacterium glutamicum, is a gram-positive microorganism which is widely used for the production of L-amino acids and other useful substances. In order to produce L-amino acids and other useful substances, various studies have been conducted to develop high-efficiency production microorganisms and technology for fermentation processes. For example, methods for specifically approaching target substances by increasing the expression of genes encoding enzymes involved in L-lysine biosynthesis or by knocking out genes unnecessary for biosynthesis have been mainly used (Korean Patent No. 10-0838038).
Meanwhile, among the L-amino acids, L-lysine, L-threonine, L-methionine, L-isoleucine, and L-glycine are amino acids derived from aspartate (Asp), and these amino acids commonly use aspartyl phosphate (App) produced from Asp by aspartokinase (LysC, E.C. 2.7.2.4) (FIG. 1). Therefore, in order to produce the amino acids by a microbial fermentation method, it is essential to maintain the activities of enzymes used in the biosynthetic pathway at a certain level or higher, and thus intensive research has been carried out in this regard.
In particular, the activity of LysC, which acts as the first enzyme in the biosynthesis pathway of aspartate-derived amino acids, is known to be regulated by feedback inhibition of L-lysine and L-threonine (J Mol Biol. 2007 Apr. 27; 368(2):521-36. Epub 2007 Feb. 20). In this regard, although applications relevant to the feedback inhibition have been filed (U.S. Pat. No. 8,062,869 B and Japanese Patent No. JP 3473042 B), continued research is still required for increasing the productivity of aspartate-derived products.
Under such circumstances, the present inventors have completed the present disclosure by confirming that production of aspartate-derived L-amino acids or amino acid derivatives thereof is improved when using a novel aspartokinase variant.